Techniques for variably controlling power generation of an alternator have been applied to improve fuel efficiency of a vehicle by preventing the power generation during acceleration or by maximizing the power generation to charge a battery during deceleration. That is, during acceleration, a mechanical load applied to the vehicle is reduced by controlling the power generation of the alternator in order to improve acceleration performance. During deceleration, deceleration performance is improved by using torque generated by the maximum power generation of the alternator, thus improving the fuel efficiency of the vehicle.
Previously, in controlling power generation of a vehicle, an alternator and an engine control unit (ECU) control the power generation using analog waveform signals (pulse width modulation (PWM)) through multiple wires. The multiple wires include an FR-line for transmitting a signal indicative of a state of power generation of the alternator to the ECU, and a C-line for transmitting a signal relating to the control of power generation to the alternator.
However, recently, local interconnect network (LIN) communication, which transmits and controls digital values using a LIN communication line, for an alternator has been developed. Here, the alternator includes a regulator for controlling power generation. The regulator controls the power generation by transmitting and receiving information to and from an ECU. The regulator has a load response control (LRC) function, which prevents rapid variation in an electric load applied to a vehicle. When the electric load is generated rapidly while the vehicle travels, the alternator generates a torque for the power generation, and at this time, the engine revolutions per minute (RPM) changes rapidly. Therefore, the LRC function gradually increases the power generation of the alternator when the electric load is rapidly generated, thereby reducing variation of the engine RPM of the vehicle.
According to the related art, a constant LRC value is used for the LRC function. In other words, the duration for which the power generation of the alternator gradually increases is applied consistently. The LRC value is fixed as an optimized value by testing a vehicle and predicting variation in the engine RPM according to the variation in the electric load of the vehicle, and by predicting a state of illumination of a headlight or a dome light.
However, since a fixed LRC value is used, charging performance of a battery is unnecessarily deteriorates. Thus, using variable LRC values may increase efficient, for example, a battery can be stably charged using a lower LRC value regardless of variation in electric load and a vehicle RPM can be stably realized using a higher LRC value regardless of load variation according to increase in the power generation.
The foregoing is intended merely to aid in the understanding of the background of the present disclosure, and is not intended to mean that the present disclosure falls within the purview of the related art that is already known to those skilled in the art.